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Alignment, body mass and their interaction on dynamic knee joint load in patients with knee osteoarthritis

journal contribution
posted on 06.12.2017, 00:00 authored by R Moyer, T Birmingham, B Chesworth, Crystal KeanCrystal Kean, J Giffin
OBJECTIVE: To examine the interaction and relative contributions of frontal plane alignment and body mass on dynamic knee joint loading in patients with knee osteoarthritis (OA). METHODS: We completed three-dimensional gait analyses and hip-to-ankle standing anteroposterior radiographs on 487 patients with knee OA referred to a tertiary care center specializing in orthopaedics. RESULTS: Using sequential (hierarchical) linear regression, the interaction term (mechanical axis angle x mass) contributed significantly (P<0.001) to a model (total adjusted R(2)=0.70) predicting the external knee adduction moment, that included mechanical axis angle (R(2)=0.37) and mass (R(2)=0.06) while controlling for age, sex, height, Kellgren and Lawrence grade, pain score during walking, gait speed, toe out angle and trunk lean (R(2)=0.25). When the sample was split into tertiles for mass, mechanical axis angle accounted for 32-54% of explained variance in knee adduction moment. In the tertile with greatest mass, results suggest a 3.2 N m increase in knee load for every 1 degrees increase in varus alignment. When split into tertiles for mechanical axis angle, mass accounted for 6-10% of explained variance in the knee adduction moment. In the tertile with the most varus alignment, results suggest a 0.4 N m increase in knee load for every 1 kg increase in mass. CONCLUSION: Our findings describe the interaction between alignment and body mass on dynamic knee joint loading, with the association between alignment and load highest in patients with the highest mass. Our findings also emphasize the role of malalignment on knee load at all levels of mass, and have implications for better understanding risk factors and intervention strategies for knee OA.

Funding

Category 1 - Australian Competitive Grants (this includes ARC, NHMRC)

History

Volume

18

Issue

7

Start Page

888

End Page

893

Number of Pages

6

eISSN

1522-9653

ISSN

1063-4584

Location

United Kingdom

Publisher

Elsevier

Language

en-aus

Peer Reviewed

Yes

Open Access

No

External Author Affiliations

TBA Research Institute; University of Western Ontario;

Era Eligible

Yes

Journal

Osteoarthritis and cartilage.